XSLT Cookbook

Generating Code from UML Models via XMI

Problem

You want to generate code from Unified Modeling Language (UML) specifications but are unhappy with the results produced by your UML tools’ native-code generator.

The State Design Pattern

A state machine is a useful design tool that directly models a software system whose behavior changes over time as various events unfold. A state machine is often depicted as a graph where vertices (nodes) designate specific states and where edges (links) specify transitions between states in response to a stimulus or event.

The state design pattern approaches the construction of a state machine by representing the concrete states by distinct classes that derive from an abstract base State class. A separate StateMachine class represents the state machine as a whole and holds a pointer to a concrete State that represents the current state. Methods in the StateMachine defer to the current state to implement state-specific behavior. Invocation of these methods may cause the concrete state class to transition its owning StateMachine to a new state.

Solution

XMI is a standard XML-based representation of UML that many UML modeling tools (such as Rational Rose) support. Although the stated purpose of XMI is to allow interchange of modeling information between different tools, it also can be the basis for code generation.

Most UML tools support code generation but rarely generate more than a skeleton of the object model. For instance, all UML-based generators ...